There are presently many recombinant polypeptides and proteins used therapeutically to treat a number of diseases. These recombinant polypeptides and proteins are all commercially manufactured using either primary, continuous non-human, or human diploid cell lines. For instance, some are manufactured using bacteria such as E. coli, while others are manufactured using yeast or various ovarian cell lines of animal origin. Bacteria cannot be used for the manufacture of some polypeptides and proteins particularly when glycosylation patterns and other protein modifications are critical for biologic-receptor binding affinity, biologic activity, biodistribution or pharmacokinetics of the biologic or for recipient immune recognition. When glycosylation is a critical variable, the Chinese Hamster Ovary Cell is currently one of the most commonly used cell lines for biologic manufacture.
Unfortunately, the need to use a recombinant polypeptide or protein for long periods of time or for chronic therapy can result in the patient developing neutralizing antibodies to the product, making the patient less responsive or unresponsive to the drug. In some cases the patient can switch to another drug in the same class, such as with the variety of anti-TNF biologics, such as Enbrel, also known as Etanercept; Remicaide, also known as Infliximab; Certolizumab, and Humira, also known as D2E7, that are used to treat diseases such as rheumatoid arthritis, juvenile rheumatoid arthritis, psoriasis, psoriatic arthritis, ankylosing spondolytis, ulcerative colitis and Crohn's disease routinely. However, generation of neutralizing antibodies to one particular anti-TNF biologic in general predisposes the patient to ultimately generate neutralizing antibodies to another anti-TNF biologic product. In some instances, there are no alternative treatments for the patient, so this neutralizing antibody formation leaves the patient without treatment options. Even when there are appropriate treatment options, the pre-disposition to developing neutralizing antibodies to other drugs in the same class ultimately means that these patients may be left without treatment options.
Other biologic products that can be neutralized by human antibodies include: Natalizumab, or Tysabri, an innovative therapy for multiple sclerosis, and Denosumab, a fully human monoclonal antibody to receptor activator of nuclear factor kappa-B ligand (RANKL), approved for the treatment of osteoporosis and chemotherapy-induced bone fracture, with potential use to treat breast cancer caused by HRT and hormonal contraceptives. Abatecept is a CTLA-4 fusion protein approved for use in rheumatoid arthritis patients who have become refractory to anti-TNF therapies. Although its use is too new to have evidence about Abatecept induced neutralizing antibodies, it also has the possibility that it may induce a human antibody neutralizing antibody reaction.
Other polypeptides and proteins besides the antibody and fusion protein based drugs have also been shown to elicit immune responses with long-term treatment. For instance, recombinant human erythropoietin elicits neutralizing antibody formation that reduces its efficacy and can lead to a rare aplasia syndrome. Also, the generation of antibodies to coagulation factor therapy for hemophiliacs is as high as 25-30% of the patients. This is a general problem wish the coagulation factors. Recombinant interferon alpha 2a therapy for cancer and hepatitis B also are hampered by the generation of neutralizing antibodies to the treatment. Refractoriness to long-term growth hormone therapy for children with short stature is also problematic. There are reports of neutralizing antibody formation to some insulin products.
Other biologic drugs that have the potential to elicit neutralizing antibodies include whole blood, serum, plasma pools or other primary sources of biologic supply, for instance, human albumin, human Alpha1-Proteinase inhibitor, human Antihemophilic Factor/von Willebrand Factor Complex, BabyBig Botulism Immune Globulin Intravenous, C1 Esterase Inhibitor, fibrin sealant, fibrinogen, Immune Globulin Intravenous, Immune Globulin Subcutaneous, Protein C Concentrate, Rho(D) Immune Globulin Intravenous, thrombin, von Willebrand Factor/Coagulation Factor VIII Complex.
Recombinant polypeptides and proteins elicit immune responses and neutralizing antibody generation based on multiple characteristics, including: the time frame of biologic treatment, the interval of repeat therapy, the amino acid composition of the biologic, and the modifications to the biologic such as glycosylation, methylation, nitrosylation, sialylation, phosphorylation, sulfation, prenylation, selenation, ubiquitinylation, vitamin-dependent modifications, protein binding associations, acylation, glycation, 3 dimensional configurations and supercoiling. Thus there is a need for methods of producing polypeptide protein products having reduced levels of antigenicity in an animal being treated with a biologic product.
The teachings of all of the references cited herein are incorporated in their entirety herein by reference.